Several U.S. patents are known which deal with wet vacuum machines where liquid is sprayed onto the surface to be cleaned in the vicinity of a suction head. These patents include the following U.S. Pat. Nos.: 1,059,136 to Gafney; 2,972,769 to Keating, et al.; 3,496,592 to Jones; 3,687,729 to Winburn, et al.; and 3,909,197 to Cremers.